The present invention relates to an electrical subassembly having a holding device and an electrical component fastened thereto.
It is conventional to mount relatively heavy electrical subassemblies, such as large capacitor subassemblies, on a carrier substrate, such as a printed circuit board, using a holding device. The subassembly including holding device and electrical component can then be mounted on the printed circuit board in a simple way, using, for instance, the SMD technique (surface mounted device). Such a subassembly is described, for example, in German Published Patent Application No. 198 14 156, which shows an electrical subassembly having a frame-like holding device with a central opening into which an electrical component has been set. The electrical component is a capacitor in this case, whose contact elements are connected to conducting contact surfaces of the holding frame. The contact surfaces, in turn, are conductively connected, each to one contact on the underside of the holding frame, via conductive sections of the holding frame. When the subassembly is mounted on the printed circuit board, the contacts of the subassembly are soldered to the associated printed circuit trace on the printed circuit board using the SMD technique, so that the electrical component is electrically connected to the printed circuit traces of the printed circuit board. This mounting method has the disadvantage in that the components must first be soldered to the holding frame, and then, a subsequent renewed soldering procedure is required for soldering the contacts of the holding frame to the printed circuit traces. It is also a disadvantage that the soldered joints between the contacts of the subassembly and the printed circuit traces of the printed circuit board are used at the same time for the mechanical fastening of the subassembly. In this case, vibration and shaking loads, such as occur in a motor vehicle, are directly transmitted to the soldered joints. Thus, the possibility of damage to the soldered joints and impairment of the electrical connection between the component and the printed circuit board cannot be excluded.
In the case of the electrical subassembly according to the present invention, the disadvantages of conventional arrangements are avoided. Since the contact is formed by a bent-off section of the at least one contact element of the electrical component arranged on the support surface, the mechanical fastening may be separated from the electrical connection of the component to the printed circuit board. Since the holding device used for mechanical fastening has no electrically conductive device, the shaking loads and the vibrational loads transmitted to the holding device may be kept away from the electrical junctions. Furthermore, the subassembly may be inserted on the carrier substrate as a preassembled unit. Fixing the electrical component to the holding device may be performed out with special ease, since the component is only inserted in the holding device and subsequently the contact elements of the component at the holding device are bent over. An additional soldering procedure is thus not required. In addition, by the special position of the bent-off ends, the contact elements may be reliably contacted to the printed circuit traces of the carrier substrate when mounting the electrical subassembly on a carrier substrate.
An especially secure holding of the subassembly on the carrier substrate is achieved if the holding device may be mechanically fastened to the carrier substrate using fastening means having screw threads.
The bent-off section of the at least one contact element may be arranged parallel to the support surface of the holding device, extending at least partially in a notch in the support surface, whereby the danger of damage to the contact elements during the insertion of the subassembly onto the carrier substrate is avoided.
During the mounting of the subassembly, secure contacting of the contact elements to printed circuit traces of the carrier substrate is made possible by the fact that the bent-off section of the at least one contact element, in the unmounted state of the subassembly, has one part projecting outwardly.
The part projecting from the support surface in the unmounted state of the subassembly of the bent-off section of the at least one contact element may be lowered into the notch when it is rested on the even carrier substrate. This measure makes it possible to press the support surface of the holding device with great force onto the carrier substrate achieving a particularly firm mechanical connection without stressing the electrical bonding sites by using a fastening arrangement (e.g., a fastening arrangement having screw threads). For this purpose, the notches in the support surface of the holding device have a depth and breadth which is dimensioned larger than the diameter of the bent-off section of the contact element.
In an example embodiment of the present invention, the holding device includes two spatially separated holding parts each having a support surface, the two holding parts being fastened spatially separately to the end face ends of an elongated electrical component, such as a capacitor. Thus, for example, large cylindrical capacitors may be inserted on the carrier substrate along an axis aligned parallel to the carrier substrate.
The two holding parts may have elastically flexible clamping arrangements configured to fix the electrical component.
Each holding part may include a beaker-shaped foundation having a base plate and a sidewall extending around it. The end face ends of the electrical component may be inserted into the beaker-shaped base elements. By a suitable selection of the distance between the support surface and the beaker-shaped receptacle for the component, it is possible to arrange other subassemblies on the carrier substrate, under the electrical component.
The sidewalls of the two holding parts may be subdivided into a plurality of clamping tabs by making slit-like cutouts, which makes possible a reliable and stable fixing of the electrical component to the holding device.
Furthermore, each holding part may include a projection on the side opposite the component, which has a through hole extending parallel to the base plate and perpendicular to the support surface of the respective holding part for putting through a screw.
Since each holding part has a spigot projecting from the support surface for inserting into a hollow recess in the carrier substrate, it is possible to fix the subassembly to the carrier substrate using the spigots, and subsequently to produce a soldering connection of the contact elements to the carrier substrate and to connect the subassembly to the carrier substrate using fastening means having screw threads.
At least one holding part of the subassembly may be equipped with at least one opening used for guiding through the at least one contact element projecting from the end face end of the electrical component. After the component has been pushed into the beaker-shaped holding parts, the at least one contact element may be bent off toward the support surface after the opening, and bent off again in the plane of the support surface. These measures may be performed cost-effectively in an automated line production without additional cost.